1. Field of the Invention
The present invention relates to an organic light emitting diode (OLED) display. More particularly, the present invention relates to an OLED display having a touch panel.
2. Description of the Related Art
An organic light emitting diode (OLED) display includes a plurality of organic light emitting diodes (OLEDs). Each of the OLEDs includes a hole injection electrode, an organic emission layer, and an electron injection electrode, and light is emitted by energy that is generated when an exciton generated by coupling of electrons and holes falls from an exited state to a ground state within the organic emission layer.
Because the OLED display is a self-luminance display (due to its ability to self-generate light) and does not require a separate light source (unlike a liquid crystal display (LCD)), thickness and weight thereof can be reduced. Further, because the OLED display has desired display quality characteristics, such as low power consumption, high luminance, and high reaction speed, the OLED display is appropriate for use as a next generation display in a mobile electronic device.
In general, the OLED display includes a panel assembly in which a plurality of OLEDs are formed, a bezel coupled to the panel assembly at a rear side of the panel assembly, and a printed circuit board (PCB) that is electrically connected to the panel assembly through a flexible printed circuit board (FPBC).
As a new input method that can replace a conventional input method (e.g., mouse or keyboard), a touch screen enables direct input of data to a screen by using a hand or a pen. Particularly, the touch screen enables a user to directly perform desired work while viewing the screen, and it is easy to operate so that it has been evaluated as an ideal input method for a graphic user interface (GUI). It has been used in various fields such as mobile phones, PDAs, terminals in banks and public offices, medical equipments, and information display devices in tourist agencies and other suitable agencies.
The touch screen can be broadly classified as one using a resistance film method, a capacitance method, an ultrasonic wave method, or a light (infrared) method. In the resistance film method, two substrates (each of which is coated by a transparent conductive layer) face each other, and a dot spacer is interposed therebetween.
According to the resistance film method, an electric signal is applied to one of the transparent conductive layers for detecting a location, and a user presses an upper substrate with a finger or a pen. Then, the transparent conductive layer of the front substrate contacts the transparent conductive layer of the rear substrate so that the opposite transparent conductive layer detects the electric signal. Here, a location is detected by using the intensity of the detected electric signal. However, the resistance film method has low detection accuracy because the intensity of the signal varies in accordance with the applied pressure. Further, when the user presses the touch panel, the press load is directly delivered to an OLED panel, which may damage the OLED panel.
In the light method, a photo sensor is provided to detect variation of incident light and generate a corresponding electric signal, and a location is detected on the basis of the electric signal. According to the light method, the touch screen can provide high detection accuracy because a signal is generated not by pressure but only by contact. However, the light method may be influenced by light emitted from an OLED, thereby causing malfunctions.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and may contain information that does not form the prior art.